1. Field of the Invention
The present invention relates to a method for assisting the driver of a motor vehicle during a driving maneuver. e.g., a parking process.
2. Description of Related Art
Different systems are known for assisting a driver during a parking process. These systems assist the driver especially during parking in a parallel parking space. In such systems, while the car is passing a parking space, the distance from objects next to the vehicle is usually measured by a sensor mounted on the side of the vehicle. With the aid of the signal curve ascertained, it is detected where there is a suitable parking space.
When one parks in a parking space thus ascertained, the system for assisting the driver of the vehicle, during the parking process, takes over the actual steering process, while the driver merely has to operate the brake and the accelerator. The steering intervention by the system, in this context, takes place so that the vehicle to be parked both steers past objects bordering on the parking space and also finally stands parallel to a roadway border, such as a curb. Alternatively to systems in which the steering process is taken over by the vehicle, systems are also on the market in which the driver still has to steer himself, but receives instructions from the system as to how he has to steer in each case so as to enter into the parking space.
However, since only a part of all parking spaces are parallel parking spaces, systems are further known which besides parallel parking spaces also detect perpendicular parking spaces. Driving into such perpendicular parking spaces preferably takes place backwards, in this instance. For this parking process, assistance to the driver should also be offered.
In order to be able to assist the driver during parking, it is necessary that the system detects whether a parallel parking space is present or a perpendicular parking space. A method is known, for instance, from published German patent application document DE 10 2005 032 095, in which the alignment of a vehicle bordering on the parking space is ascertained, and from the alignment of the vehicle one draws a conclusion on the orientation of the parking space.
The disadvantage of the known system is, however, that not only parking spaces are detected, using the known systems, but also free regions that do not represent parking spaces. The reason for this is particularly that, when ultrasonic sensors are used as distance sensors, a perpendicularly parked vehicle in the ultrasonic sensor image cannot always be reliably distinguished from other objects, such as round ones. In addition, based on the depth of a perpendicular parking space, a curb can generally not be detected by the ultrasonic sensor, and its detection may consequently not be made a condition for the existence of a perpendicular parking space. This leads to individual objects, which in the ultrasonic image resemble a perpendicularly parked vehicle, being sufficient for outputting a perpendicular parking space. The quality of the parking space indication is thereby drastically reduced.